Centering device for gripper bars in sheet handling machines



June 20, 1950 H. BoBsT 2,512,084

CENTERING DEvIcE EoR GRIPPER BARS IN SHEET HANDLING MACHINES lorneys June 20, 1950 H. BoBsT 2,512,084

CENTERING DEVICE FOR GRIPPER BARS IN SHEET HANDLING MACHINES Filed April 19, 1946 z sheets-sheet 2 Patented June i20, 1950 "cENTiranteDavion FOR GRIPPER BARS 1N v es HEE-TJHANDLNGMAGHINES y y f Henri-a,BobstaLausalisswitzerland *This* last` operation;A hasf-already" been --ifected l `by means of- 'conical''centering` dowels penetratfing E'into corresponding openings -of the bars. LHowever,A- 4this *devicelis lmnt-very-l satisfactory fas VVtheresistance vopposed by-'the tension`to the `pen'etration of Vthe dow'el can-easily 4produc-:eran awkward raising of the "bars','fwhereas"fthe pin cone must be able to provoke -a-'-'suicientffdis `rilacement'of the bar soas 'to' compensate-the Igreatstretching vto which the fc'hainsfare subject aft'era;'certain4 use. This isco'ntrary to` the-condi- "tion of -being able `izo-overcome the tension :to Y"which" `:the chains are -submitted,^which fcan ivin Tant only 'befeiected 'by' a relativelyftaper#cone, A`andtthisnot -Wthoutihard Wear. f The distances Jof" the'- pins must alsobeveryf exactlyf determined Which Acreates certain `difficulties lan'df moreover `the=who1e f device Workstat a disadvantage kowing tothe presence of dust-from the fcardboardbtvhi'ch isbeing'worked v "''l'.estshave` already been vIna-de vin 'orderito center :the bars by acting onthe links othe 1 chains, "but the `play-fand lnoteroundaworkingiffas :Well as vthe'raising of"`1these llatter, are'other4r cau-ses Aof inexactitude. ItV is fthe same for lth'eflockingiof 'thedr'ving Wheels,v inl'order -to Alimmobilzef'ai#cerianf.number of links, orfrfthel @bari itself, fwhen fenggedlintheir teeth. r v

Thef- 'obj ect *of `the linvention s` ito vrepla'cefall thesedispositions by 'positive 'abutmentsjwhich are `piaced 'on the"trajectory:-of11the extremities -iifi'the'lbars -in the immediate lneighbourhoodof 'Tat Ieas'tfone of their l stations, *abutments' against -which f pressingy organs provoke 'the supportioffa predeterminedpart 'of ikthel said extremities; by :disr.flila'lcngA TftheFbars forlsucl'iV af` quantitydfthat y'zthe 3normal-1y' stretched chainfli's bligedto yieldup.

v(This A'operation f- Will generally 'be"5 executedt sir-xx'nilta-nemisly- Lat thea margin stationiiandat lthe 12 i abutmentsxcould foriexampleibe Vcarried alongxby the movable p1atof;the:press. 1

' 'Iihefannexedfdrawingxshowsgan'embodiment of ithe object y. of ',Lthe: invention, given :.Jby f way :gaf

example.

:Fig.s;1-: shows that :part -ofl the,` device which is atthefregistering :stationpzbefore "a bar. arriices. -;:-Fig. 23 shows' the -same gpa-rtfoperating :the centering of a bar which i Fig.,;=3 showswinfplanepfview.

Fig. 4 shows fthe centering I 'of Y g a vfliar L: at tithe: .workngzr station. e

Figa. iss.aucOrreSpOndingwpIane viewzfand -,-i'-Fig.'f-6 ffa-'rcomplete viewzoffthe :press showing: `-tlriefdi.Stribu-t'onof the 'described' parts. i

lThe part of-itheftdevice represented; on yli-gs .p1

wand 'f2-sis -f composed of'ithe registeringboard If,

`:show-n in l:tramwersal f :cross .Y fsection, and which oscllates around the pivot 2 under the yaction of; a r-leverr and of a driving 'connectingfrod-y 3.

.'Ihis;` boardA bears3'forwardrregistering worked, l`which position fcanfbe exactly adjusted; fand the .abutmentl 5, idestined.v to provoke the openingnof the.;I grppers offthe bars. carried between f-:two

chains, one of which 6 is to be seen.

'Thewboar'd I bears also, iat :,eachffextremity, a

-Jcam ',1, against which leans ',afrollen- 8,Vl Whichian tlasticfbladeiconnects withr a sleeve l0 joinedto a lever ending at one of its extremities :byxethe :hook 1' vlzl ,mand at thefopposite extremity; hby@ an #elongated 'eyelet into: Iwhich penetrates asroller lZf'joineditoacrankedlever'I'3. i y

y'lliis Yle-veryvvhich*turns; around :the :sha'ft,|4, ,penetratesintoaanaxially :sliding -rod 5ft-:the upper extremity of which ends vby :ai'atz part IB. .fA'spring H seeks-tofbring fthehwhole back-sto the ,resting'position shown on Fig.' 1, i. e; rod .f1.5 rbeingidownraridnhook `Il drawn "backwards," in @ordertorgiveV freemassage'ato. axbar by the chains. But as, .soonzas tsuch ai bar yreaches :the position L Hicofr Fig. '-2,-.i.e e, isiplaced abet-ween the, prolonga- :tion fof. therfiat fpart, of vrod I5 `and the-"hooky 1M, the connecting rod 3 bringsthe:-registeringaboard Ifback to its `vhorizontal position, yWhich lhaszfor Azresultzf, to-1a11ow. :the :forward registering marksi i4 working-station..LAtfthisllatten poi-nafther-.po'sitive iu rzssheet,y morrectlx/.zxesistered.fcbmtheiifamaid before the pressure exerted -by hook Il be supi`v pressed.

It is also evident that the must be able to overcome the tension which is communicated to the chains inforder to'l allowl described mechanisrnj.1

of the slight backward movement ofmthe bar l8r ensuring thus its application'against fthe flat; .3.'

parts I6.

These latter forming positive abutments of'suf- From there,the bar goes to the working station II and passes between the upper fixed plate and the mobile lower plate 2l, driven by toggle joints 22. f Fig. 4 shows in detail .how the bar is agai centered on arrivingat this station. i

Stopping at I8', immediately behind the lower mobileaplate 2l, the lbarl is caught at each extremity between a key 23 of the plate and the hook 24 of a lever positively operated by the intermediary cfa driving connecting rod 25 and of an elastic joint 26, kthis hook being normally drawn backward in order to give free passage to the bars. l

The plane view of Fig. shows'obviously the position ofthe chain 6, of the bar i8',-of plate 2l; of key 23, of hook 24 and of shaft 21,common tothe tightening levers affecting both extremities of the bar and supported by brackets joined to the plate. i

In. fact, it is necessary that the key and the grippers move upward and downward with the plate, yin order to oblige the bar to follow this movement.

. V:At this station, as well as at the first one, the

support of the bars is carried out in a positive manner against a surface largely dimensioned.

- It is obvious that the obtained .backward movement'of the gripper bar must be slightly'greater in station II than in station I, in order that the section of' the chain, comprised between these two stations, may be very slightly-slackened.

This will always be the case if the chains are driven in I by means of the wheels 28, the chains being stretched in 29 by the springs 3B. L Would the driving be elsewhere effected, .this would only have for consequence, should the case happen. to' necessitate the inversion of the action of the describedidevice, i. e. the positive abutment would come behind the bar,.instead of in front of it, and the pressing organ would be placed in front instead of behind. n .AIhedescribed centering action has an innuence on the position of the extremities ofthe bars in the carrying direction. It can also'be useful to ensure its exact position on a transversal direction with regard to the carrying direction;

In the described examples, this result is obl'ainedfin-y the-.two stations aby makingthe .bar

immediate lvicinity of at least one working stapass between a fixed abutment 3l of the machines frame and a block 32 submitted to the action of a spring 33 and operating on the bar a lateral pressure, which obliges it to lean against the abutment 3 I.

What I claim is: Y

1. In a press or the like for working sheets car- "y, ried4` by gripper bars, wherein the bars are conveyed by a pair of parallel chains, each-of said chains being trained over a driving sprocket and provided with tensioning means for taking up the slack. therein; a centering device located in the tion of the 'press comprising positive abutments movable into and out of the path of travel of the `Ebars at Ithe extremities thereof and at the side of `theba'lrs facing 'away from the direction in which the chains lare tensioned, means moving said abutments into and out of the path of travel of said bars, and means pressing said bars against saidpositive abutments in oppositionto the ten- -sioning means to thereby center said bars@ p 2. A press or the like for Working sheets comprising gripper, bars for carrying the sheets through the press, a pair of continuous parallel chains conveying said bars, a driving sprocket for each of said chains over which the latter are trained, tensioning means engaging each of said chains `and taking .up the. slack therein, anda centering device located in the immediate vicinity of atleast one working station of the press including positive abutments movable into andzo'ut of the path yof travel of said bars at the extremities of the latter and at the side of the bars facing away from the direction in which the chainsare urged by saidtensioning means, means moving said abutments into and out of the path of Atravel of said bars, andvmeans pressing sai-d bars against said positive abutments when the latter are positioned inthe vpath of travel of said bars and'in opposition. to said tensioning means to thereby center said bars. s y

3. A press or the like for working sheets comprising an upper xed platen and a lower movable platen; a pair yo fparallel continuous chains having runs in afplane passing between the confronting surfacesof said upper and lower platens;` a driving sprocket for each of said chains over which the latter are trained; tensioning. means lengaging each vof said ,chains for takingl up the slack therein; a plurality of gripper-.bars carried by said chainsbetween said upper and lower platens and spaced apart a distance substantially greater than the length of said platens; first centering means at the sheet taking station in advance of said platens including positivev abutments moving into and out of the path of travel of said bars at their extremities and at the side of said bars facing away from the directiony in whichthe chains are urged by said tensioning means, and 4means pressing the bar at said sheet taking station against said positive abutments when the latter are disposed in the path'of travel;

and secondcentering means at the working station ,immediately after said platens including positive abutments moving into and out of the pat-h of travel of said bars at their extremities and at the side-thereof facing away from the di rection -in which said chains are urged by said tensioning means, the distance between said positive abutments of said rst centering means and s aid last mentioned positive abutments being less than the spacing between Aadjacent ones of said gripper barsas carried by said chains, and means 'Il pressing the-bar at-the workinsstabion. against said last mentioned positive abutments simultaneously with the operation of the first mentioned pressing means whereby said bars are centered against the action of said tensioning means and the portions of the chains between said working station and said sheet taking station are rendered slack to permit centering of the gripper bar at the latter station.

4. A press or the like for working sheets according to claim 3; wherein each of said gripper bars include gripper fingers normally spring urged to closed position and a gripper opening plunger engaging each of said ngers; including a transverse oscillating registering board immediately in advance of said sheet taking station having lugs thereon contacting said gripper opening plungers for opening said fingers when said board approaches its upward terminal of oscillation, sheet registering stops for registering a sheet at said sheet taking station while said gripper fingers are open, and an operating cam for actuating said iirst centering means; and wherein said first centering means includes a rockable shaft, a resilient arm extending radially from said shaft, a cam follower on said resilient arm engaging said cam on said registering board whereby said shaft is rocked in response to the oscillation of said board, said pressing means including levers mounted on said shaft and having portions thereof swinging into the path of travel of the bar as said sheet taking station and against the side thereof facing in the direction of the tensioning of said chains, and means operatively connected to said shaft moving said positive abutments into the path of travel of said bars simultaneously with the swinging of said lever portions into said path of travel whereby the bar at said sheet taking station is centered simultaneously with the registering of a sheet by said registering board.

5. A press or the like for working sheets according to claim 3; wherein said positive abutments of said second centering means consist of keys fixed to the trailing edge of said lower movable platen and moving into the path of travel of said bars when said lower platen is raised; and wherein said pressing means of said second centering means includes a transverse shaft rockably carried by said lower platen, means oscillating said shaft simultaneously with the raising of said lower platen, pressing levers on said shaft resiliently connected to the latter and swinging into the path of travel of the bar at said Working station and against the side thereof facing in the direction of the tensioning of the chains for urging said bar against said keys whereby the bar at said working station is centered relative to the platens.

6. A press or the like for working sheets according to claim 3; including transverse centering means at said sheet taking station and at said working station engaging the opposite ends of the bars at said sheet taking and working stations tc thereby center said bars in a direction at right angles to their direction of movement through the press.

HENRI BOBST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED 'STATES PATENTS- Number Name Date 2,138,405 Huck Nov. 29, 1938 2,221,500 Upham Nov. 12, 1940 2,258,880 Bobst Oct. 14, 1941 

